Originally Posted by MarkGideon

The Nismo muffler has one hanger bracket a bit different from the base muffler. On the Nismo there is an added piece of flat metal to drop the mounting hole a bit for the bracket on the front of the muffler to attach to using the small stock insulator. If you are selling the Nismo to a base owner, you can save them the trouble if you can remove the bracket from the Nismo frame and send it with the muffler.

Check this thread for what may happen without it, and my post in that thread for an inexpensive fix if you don't have the bracket.

Nismo exhaust install possibly went wrong. Fitment issues from NismotoBase?